html, body {
    margin: 0;
    padding: 0;
}

body {
    padding-top: 20px;
    background: #EEE;
    font-family: monospace;
    font-size: 12pt;
    color: #000;
}

div#container {
    margin: 0 auto;
    padding: 10px;
    width: 580px;
    background: #DDD;
    border: 1px solid #000;
    border-radius: 8px;
}

h1 {
    margin: 0 auto;
}

a {
    border-bottom: 1px dashed #000;
    color: inherit;
    text-decoration: none;
}

a:hover {
    background: #FFC;
    border-bottom-color: #00F;
    color: #F00;
    text-decoration: none;
}

input {
    font: inherit;
}

input.text {
    background: transparent;
    border: 1px dotted #000;
}

input.text:focus {
    background: #FFC;
    border: 1px solid #000;
}

input.wrong-text {
    background: #F99;
    border: 1px dotted #F00;
}

input.wrong-text:focus {
    background: #FCC;
    border: 1px solid #F00;
}

p.error-text {
    font-size: 75%;
    color: #F00;
}

table {
    margin: 0 auto;
}

td {
    vertical-align: top;
}

td.label {
    padding-right: 5px;
    text-align: right;
}

td.value {
    padding-left: 5px;
    text-align: left;
}

td.perform {
    text-align: right;
}

span.operand {
    background: #FFC;
}

span.result {
    background: #FF0;
    font-weight: bold;
}